It has long been known that railroad ties which are worn, damaged or rotted should be removed from and replaced in an existing rail bed. In order to replace such a tie, it is necessary to remove any spikes which hold the tie fixed with respect to its associated rails, remove any ballast, gravel or other debris from the vicinity of at least one end of the ties, if desired jack up the track located over the tie to create additional clearance to permit the removal of the tie, and then longitudinally extract the tie from under the rails.
Over the years, many devices have been suggested for use in extracting railroad ties. For example, in U.S. Pat. No. 317,829 (Mergenthaler), dated May 12, 1885, it was suggested that a tie extractor could be provided consisting of a jawed bearing bar, a beaked rack-bar sliding thereon, a lever link pivoted on the rack-bar, and a gear lever pivoted to the lever-link and engaging the rack/bar. By applying the jaws of the bearing bar over the head of a rail, and piercing the top surface of the underlying tie with the beak formed on the rack-bar, it was possible, through manipulation of the lever and gear mechanism, to cause the translation of the underlying tie with respect to the track.
In concept, the Mergenthaler tie extractor and replacer is similar to a number of devices which were designed to be dedicated solely to the task of extracting and replacing railroad ties. For a description of such devices please refer to U.S. Pat. Nos. 632,300 (Zetter), 637,843 (Zetter), 1,468,231 (Goldbeck), 1,836,082 (McManus), 2,219,577 (Neely et al), 2,133,851 (Denton) and 1,822,409 (Lawrence). In these patents, devices of varying degrees of complexity are disclosed with varying means for engaging one or more of the associated railroad rails, for engaging the tie to be pulled, and for providing a mechanical advantage intended to ease the extraction of the subject tie. These patents suggest various tie or rail engaging configurations including various rail engaging bracket configurations and tie engaging claws and/or tongs. Similarly, various gear rack, rachet, screw and lever configurations have been suggested for providing the aforementioned mechanical advantage.
In spite of the many devices which have been suggested over the years for extracting ties, manually operatable tie removing devices routinely utilized by railway track maintenance crews in this country. In fact, most of the millions of ties which are replaced each year in the United States are replaced entirely by hand, that is, by using picks, shovels, and other simple hand tools to replace such ties. In fact, the only routinely used, hand operated device which provides a substantial mechanical advantage is the standard railway rail jack, which is also commonly referred to as a "track jack". One of such commonly used rail or track jack is illustrated in the FIG. 2 of this application. In FIG. 2 this rail jack (50) is illustrated as comprising an enlongated jack body (58) which terminates in a base (66) having a substantially planer jack support surface defined thereon for supporting the jack in its normal, upright position. This jack body contains a jack rack (60) having a rack head (62) which is disposed for axial movement with respect to body (58). Movement of the jack rack (60) with respect to body (58) is accomplished through pivotal movement of jack handle (52) which acts through jack socket (54) and an internal rachet and gear mechanism to cause a selective extension or retraction of rack (60) and its associated jack lifting tang (64). In normal operation, the rail jack is placed in an upright position on the ground under a rail to be lifted, with lifting tang (64) under that rail, whereupon the jack is used in a conventional manner to raise and lower the rail with respect to the ground.
It has previously been suggested to modify a track jack as to permit that jack to be used both for aligning and leveling rails and for removing and replacing ties and the like. In U.S. Pat. No. 1,646,770 (Shasteen), dated Oct. 25, 1927, a track jack was disclosed having a removable base. In this specialized jack, a longer rack-bar (22) than normal is utilized having a chain hook (23) on one end and a notched head (25) on the other. A tie hook or angular extension of the jack (16) is used to hook over a rail or tie, as shown in the figures. When it is desired to utilize this apparatus as a rail jack, the base (10b) is fitted on the upper portion (10a) so that the bill (24) of chain hook (23) can act as a lifting surface. Thus, this specialized tie pulling apparatus can be adapted for utilization as a track lifting device.
At the present time, there exists a substantial need to improve the time in which ties may be extracted and replaced during the maintenance of railway track. It may currently take a railway crew about 11/2 to 2 man-hours to remove and replace a single tie. Such work is often conducted in the vicinity of train traffic, and even on track which is not entirely out of service. Accordingly, it is important to minimize the amount, size and weight of apparatus to be used at the work site, and to ensure that such apparatus will not substantially interfere with the passage of trains over and through the work area. For these and other reasons, prior art hand operated tie pulling apparatuses have not achieved substantial degrees of commercial success.